It is possible to measure ripple. There are two ways: • Use a Multi meter. Put multimeter in AC mode and measure the DC close to the inverter. • Use VE Configure, it keeps track of ripple When measuring remember that ripple only occurs when the system is under load. The same as for voltage drop, it can only be detected when the system is under full load or is when it is charging at full current.
A small amount of ripple can exist with no measurable impact. However, an excessive ripple can have a negative impact: • The lifetime of the inverter will be reduced. The capacitors in the inverter will try to flatten the ripple as much as possible and as a result the capacitors will age faster. • The lifetime of the other DC equipment in the system will be reduced as well. They too suffer from ripple • The batteries will age prematurely, each ripple acts a mini cycle for the battery. Due to the increase in battery cycles the battery lifetime will reduce • Ripple during charging will reduce the charge power Inverters or inverter/chargers have a built-in ripple alarm. There are two ripple alarm levels: • Ripple pre-alarm: Both the overload and the low battery LEDs blink and the unit will turn of after 20 minutes. • Full ripple alarm: Both the overload and low battery LEDs are on and the unit powers down.
These are the ripple alarm levels for the different voltages:
12V
24V 2.25 3.75
48V
Ripple pre-alarm 1.5V Full ripple alarm 2.5V
3V 5V
The only reason ripple exits is when there is a voltage drop in a system. To fix ripple you will have to reduce the resistance in the path from battery to inverter and back to the inverter. For more seen chapter 2.5.
To fix high ripple in a system do the following:
• Reduce Long battery cables • Use thicker cables
• Check Fuses, shunts and battery isolator switches • Check for loose terminals and loose cable connections
• Check for dirty or corroded connections • Check for bad, old or too small batteries
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